In many medical procedures, medical personnel wish to monitor various physiological conditions that are present within a body cavity of a patient. These physiological conditions are typically physical in nature—such as pressure, temperature, rate-of-fluid flow—and provide the physician or medical technician with critical information as to the status of a patient's condition. The manner by which these types of parameters are measured and monitored should of course be as safe, as accurate and as reliable as possible.
Equipment and processes have therefore been developed for assisting medical personnel such as physicians or medical technicians in diagnosing physiological conditions of a patient. For example, sensor guide wires in which a sensor is mounted at the distal end of a guide wire have been developed. The sensor may, e.g., be an intra-vascular pressure sensor that is arranged to measure blood pressure at various points within the vasculature to facilitate locating and determining the severity of e.g. stenosis or other disruptors of blood flow within the vessels of the living body.
With reference to FIG. 1, a typical intra-vascular pressure sensor-to-physiological monitor interface system 100 is illustrated. The arrangement comprises a sensor guide wire 110, a signal converting device 120, and a physiology monitor 130. The sensor guide wire 110 may comprise a sensor element 111 arranged at the distal end of the sensor guide wire 110. The sensor element 111 may be arranged to sense a physiological variable in a living body, such as a human or animal body. The sensor guide wire 110 is a disposable device which typically includes a connector 112 for connection to the signal converting device 120. The signal converting device 120 is arranged to interface the guide wire-mounted sensor element 111 to the physiology (e.g. blood pressure) monitor 130. The signal converting device 120 may be configured to receive a signal indicative of a physiological variable sensed by the sensor element 111 from the guide wire-mounted sensor element 111. Furthermore, the signal converting device 120 is configured to process the received signal such that a normalized signal to any of multiple different physiology monitors having potentially differing signal requirements can be forwarded to the physiology monitor 130. Thus, the signal converting device 120 is configured to convert the signal indicative of a physiological variable sensed by the sensor element to a signal according to an established standard, e.g. the standard set by the American National Standards Institute (“ANSI”)/AAMI BP22-1994 (referred to the BP 22-standard in the following), which is receivable by the physiology monitor 130.
In the previously described intra-vascular pressure sensor-to-physiological monitor interface system 100, as shown in FIG. 1, the signal converting device 120 typically includes a battery (not shown) for powering the system. When such battery has been discharged, it must generally be replaced because otherwise disrupted readings could be the direct result of such discharged battery. Sometimes, the procedure of replacing the discharged battery with a fresh battery can be rather complex and/or time-consuming for the medical personnel who must perform this procedure.
WO-2008/100208 relates to a measurement system comprising a sensor wire provided with a physiological condition sensor at its distal end. The system is in particular related to a system where a transceiver unit, being connected to the sensor wire, is completely galvanically isolated from a physiology monitor. This is achieved by arranging an optical communication link for transferring the signal from the sensor to the physiology monitor. Thereby the equipment of WO-2008/100208 may be used during external defibrillation and that external devices, (e.g. the monitor) are protected against defibrillation shocks and the patient is not part of a conducting circuit.
U.S. Pat. No. 6,585,660 relates to a signal conditioning device for interfacing intravascular sensors, e.g. guide-wire mounted pressure sensors, to a physiology monitor. The signal conditioning device processor is herein power supplied by an excitation signal received from the physiology monitor.
The object of the present invention is to achieve an improved sensor guide wire device that obviates the need for complex and time-consuming battery replacement and that is less complex and thereby easy to manufacture.